The vanishing cryovolcanoes of Ceres. Issue 3 (10th February 2017)

• Record Type: Journal Article
• Authors: Sori, Michael M.; Byrne, Shane; Bland, Michael T.; Bramson, Ali M.; Ermakov, Anton I.; Hamilton, Christopher W.; Otto, Katharina A.; Ruesch, Ottaviano; Russell, Christopher T.
• Is Part Of: Geophysical research letters. Volume 44:Issue 3(2017)
• Page Start: 1243
• Page End: 1250
• Publication Date: 2017-02-10
• Subjects: Ceres -- cryovolcanism -- Dawn -- viscous flow -- thermal modeling; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL072319
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10–500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10 8 –10 9 years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable. Key Points: We hypothesize that viscous flow significantly modifies cryovolcanic structures on Ceres We find that cryovolcanoes on Ceres are modified on 10 7 –10 9 year timescales if they are >40% ice by volume Viscous relaxation as a modification mechanism is consistent with cryovolcanism occurring throughout Cerean history